Dec, 1908.] Wheeler: Studies on Myrmecophiles. 205 



Microdon globosus issuing from a hole in the woodwork of a house 

 and infers that they had been hibernating in this retreat. 



The habits of the European Microdons have been studied by a 

 number of entomologists: Bertkau (1889), Bignell (1891), Elditt 

 (1845), Gadeau de Kerville (1884), Laboulbene (1882), Mayet 

 (1882), Poujade (18830, 1883^), Schenck (1852), Verhoeff (1892), 

 Wasmann (1891, 1894), Wissmann (1848), and others. Of the two 

 common species, M. mutabilis L. and M, devius L., the former is 

 cited by Wasmann as occurring in the nests of Formica rufa, fusca and 

 rufibarbis, and of Lasius niger, brunneus and Jlavus, the latter in nests 

 of F. fusca, sanguinea (with fusca slaves) and L. fuliginosus. 



So far as I am able to ascertain, but one of our numerous North 

 American species, M. tristis Loew, has been bred from the puparium. 

 Packard ( 1869) does, indeed, figure a puparium and fly which he refers 

 to M. globosus Fabr., from a specimen taken by Sanborn at Andover, 

 Mass., but I have recently examined the specimen, which is in the 

 Museum of Comparative Zoology, and find it to be without doubt a 

 puparium of tristis. Lintner (1885) reproduced Packard's figure and 

 description, which he also erroneously attributed to globosus. Both 

 the Museum of Comparative Zoology and that of the Boston Society of 

 Natural History contain specimens of tristis mounted on the same pins 

 with the puparia from which they were reared. During May, 1907, 

 Mr. W. T. Davis reared the flies from a lot of twenty-four tristis pu- 

 paria which I found at Newfoundland, N. J., in a nest of Formica 

 schaufussi, and during the spring of 1908 I reared a number from 

 puparia found at Bronxville, N. Y., and Paterson, N. J. In both of 

 these localities the host ant was schaufussi. My collection also con- 

 tains specimens of the adult insects and puparia taken in the following 

 localities and with the following ants: Manchester, N. J., with For- 

 mica (species undetermined); Colorado Springs, with F. rufa obscu- 

 ripes Forel (July); Colebrook, Conn., with F. difficilis var. consocians 

 Wheeler (June 30); South Harpswell, Maine, with-/ 7 ', sanguinea aserva 

 Forel (July). There are puparia of tristis in the Museum of Com- 

 parative Zoology from Loon Lake, Washington; Bingham ptor.. \. Y.. 

 and Boston, Mass. (Henshaw). 



In 1906 I published a few notes on some larva; of tristis, one of 

 which lived in an artificial nest of F. consocians from July 7 till Sep- 

 tember 10. On the former date I found three young larva; in a 

 nest of this ant at Colebrook, Conn., together with some empty 



